Guido of Arezzo, possibly born in France around 990, becomes a Benedictine monk and goes to Arezzo in Italy, where he lives for many years and where, in about 1025, he perfects the staff system of musical notation.

A renowned musical theorist and an innovative teacher, he formulates the concept of a scale pattern comprising six notes represented by the syllables ut (do), re, mi, fa, sol, la, and teaches that the interval between each syllable is a whole tone except for the one between mi and fa, which is a half step.

Because singers can now associate syllables with the fixed pitches of the notes, they are able to learn melodies much more quickly and accurately than previously.

Guido’s revolutionary inventions capture the attention of the papal court in Rome, where he successfully demonstrates his techniques.

He discusses contemporary polyphony in his writings, notable the “Micrologus.”